Collapsible tap



%H. F. STAHLBRODT. COLLAPSIBIQE TAP. APPLICATION FILED MAR. I6. 192!- I 1,409,603. Patented Mar. 14, 1922.

2 $HEETSSHEET 1- H. F. STAHLBRODTL COLLAPSIBLE TAP. APPLICATION FILED MAR. 16. 192i.

1,409,603, Patented Mar. 14, 1922.

2 $HEETSSHEET'2.

: -J- 'i, ,6 -56 I i I i a |u II HENRY'F. STAHLBRODT, OF ERIE, IENNSYLVANIA.

GOLLAPSIBLE TAP.

Specification of Letters Patent. Patefited DIEM. 14, 1922.

Application filed March 16, 1921. Serial No. 452,640.

To all whom it may concern:

B it known that I, HENRY F. STAHL- BRODT, a citizen of the United States, residing at Erie, in the county of Erie and State of Pennsylvania, have invented certain new and useful Improvements in C01- lapsible Taps, of which the following is a specification.

My invention relates to collapsible taps.

The object of the invention is to simplify and render more efficient taps of the collapsible type as will be hereinafter described and claimed.

This object I accomplish by the mechanism shown in the accompanying drawing, in which:

Fig. 1 is a central longitudinal section through my improved tap.

Fig. 2 is a plan view of the head of the tool with the chaser retaining plate removed.

Fig. 3 is a detail plan of the cams for opening and closing the chasers Fig. 1 is a central longitud1nal sect1on through the chaser stem and opening and closing c'ams' Fig. 5 is a transverse section on'line 55, Fig. 1, Fig. 6 is a fragmentary view of that portion of the body containing the ad ust ing device for the chasers.

Fig. 7 is a longitudinal section through the body of the tool.

Fig. 8 is a bottom plan thereof.

Fig. 9 is a side elevation of the tool shank and its head.

Fig. 10 is a top plan thereof. I

Fig. 11 is a plan of the cap plate of the shank head.

12 is a plan of the operating head and a portion of its handle.

The body 1 of the tool is in the form of a cylinder open at its ends. The lower end of the body 1 is provided with an annular can plate 2 through the central-opening in which extends the shank 3 ofthe tool. This shank 3 is provided with a head 4 integral therewith and adapted to slide in the body 1, but not rotate. The head 4 is connected to the inner face of the cylindrical body 1 by means of pins 6. which fit in half round recesses 4' in the head 4 and bodv 1. The shank 3 is surrounded between the head 1 and plate 2 by a helical expansion spring 7 these pins 12 extending through curved slots 12" in a retaining-plate 1 1 bolted to the head 1 of tool shank 3. The pins '12,

after passing through apertures 14 in a retainingplate 14 pass through apertures 15 in an adjusting ring 15; their free ends entering curved slots 16 in the adjacent face of an annular head 17 provided with an operating handle 18 extending through a slot 18; the inner end of this handle being threaded and entering a threaded socket 19 in thestem 20 of the chaser head 21 so that the head 17 and the chaser stem 20 and its head 21 'may be rotated together by the handle 18 to wind the chaser retracting torsional spring 25 and place it under tension. The inner end of the spring 25 is secured to a fixed partition 26 secured in the body 1 by screws 27 and the outer end of the spring is secured to the inner side of the chaser head 21. The chaser head 21 has an external annular groove: 28 engaged by the inner ends of screws 29 which permit rotary movement of the chaser head and its stem. but prevent all longitudinal movement of the same within the body 1 of the tool.

The adjusting ring 15 may be set or adjusted by means of two set-screws 30, 30 extending through body 1 and engaging shoulders 31, 31 at opposite points on the periphery of said ring. Other set-screws 32. 32 pass through the body 1 and enter peripheral slots 33, 33 in the ring 15. These screws 32 and slots 33, while permitting rotary adjustment of ring 15, prevent it from all longitudinal movement within the body 1. The body 1 is provided with a slot 35 graduated as shown in Fig. 6 and through this extends the screw 36 provided under its head with an indicator plate 37 havinga zero mark 38 to operate in connection with the graduations at slot 35. After the adjusting ring 15 is properly adjusted by screws 30,

the screw 36 will be screwed up until the plate 37 is drawn firmly against bottom wall of slot 85.

The chaser head 21 is formed with a longitudinally extending boss 40 whose outer side is formed with a series of vertical curved walls 4.1 against which bear the inner straight edges of the radially sliding chaser bits 42. At the base of the bosslO the head 21 is formed with scroll cams 43 struck on the same curves as the walls 41.

The bits 12 are formed on their inner edges with slots 14, which engage these cams 13 so that the rotation of the stem 20 by the spring 25 will move the chasers radially inward away from the work. lVhen the stem 20 is rotated by handle 18 to wind the spring 25 the cam 13 will move the chasers outwardly into cutting position, at which time the inner vertical ends of the chasers will have a straight bearing engagement against the walls 41 of the head 21 so that there will be no inclined bearings between the inner edges of the chasersand the head 21 tending to move the chasers outwardly along the head causing them to tip.

The outer end of the body 1 is formed with radial slots 50 to guide the chasers 42 and the outer edges of the chasers are en-, gaged by a cap plate 51 which covers the slots 50. The base of every slot 50 is provided with a wear plate 52 for the corresponding edge of the chaser or bit 42 and other wear plates 53 are placed in the slots 50 at opposite sides of every bit 12. These wear plates 53 all have a lug or shoulder 55 into which is threaded the inner end of a clamping screw 56 to hold them in position.

the spring 7 and this in turn will cause the cap plate 14 to pull on the heads offpins 12 and retract them from the slots 16 in the .lever head 17.1,At this moment the torsion spring 25 will have been released and will quicklyrotate the chaser stem 20, and this in turn will cause the cams 14 to retract the chasers42 from the work so that the tool may bewithdrawn for another operation. To again set chasers 42 in their operative position handle 18 will be moved until the slots 16 in its head 17 register with the'pins 12, at which moment the springs 9 will pro- .jectthe pins 12 into slots .16 and so look the .tool shank 3 to chaser stem 20 so that the chasers will be firmly held against all movement during the cutting operation.

It is obvious that, instead of setting chaser stem 20 by hand, the lever or handle 18 may be actuated automatically when used in an automatic machine.

It will be seen that the chasers are moved radially entirely by a rotary movement of the chaser head and not by any longitudinal movement thereof. This afiords the strongest operative connection as well as a most simple one.

The adjusting ring 17 will be set by its screws so as to bring the pins 12 into a new relation to the slots 16 so that when the lever 18 is turned it will also turn the chaser head slightly to project or withdraw the chasers 12, but when 'the slots 16 register with the pins they will enter the slots and lock the heads 17 and 21 against further relative rotation and so the chasers will be held in their adjusted position. The purpose of the above 7 adjustments is to compensate for slight diiterences in the sizes of the chasers purpose of having slots 16 instead of round 7 holes is to make sure that the pins 12 will snap quickly into them and lock the head.

Were round holes used the quick movement of the head might cause the holes to pass over the ends of the pins before they had time to enter said holes. The adjusting means is exceedingly simple, as only a rotary ring is necessary to bring the locking pins into proper relation to the rotary lever head and the chaser head and stem rigidly connected to said'lever head, and the slight rotation of the lever head imparts the initial adjustment to the chasers which are then held by the pins against further inward and outward movement.

By merely changing the chasers the tool may be used for either right orleft threads.

TVhatI claim is: p I

l. A collapsible tap comprising a hollow body, a tool shank slidingly mounted in one end of the body and heldagainst rotation" therein, a chaser head and stem in the opposite end of the body, operative connections on the chaserhead tOiHlOVG the chasers'in and out, a spring for rotating the said chaser head and stem to retract the chasers, means for preventing the chaserstem' and head from sliding in the body, means for turning the said stem to place its spring under tension,

means fol-locking the stem turning means when its spring is under tension, means for ad usting said locking means relative to said turning means, and an operative connection between said locking means and the tool shank forreleasing said locking means.

2. A collapsible tap comprising a hollow body having radial slots inone end, a chaser head mounted in the slotted end ofthe body and having a stem mounted to turn in the body, means holding the stem and its head against sliding movement, chaser-actuating cams integral with the chaser head'topositively move. the chasers in and out 'of'the body slots, a spring for rotating the head and stem, means for placing the spring under tension, means for locking the chaser head and stem when the spring is under tension, a tool shank movable longitudinally in the opposite end of the body, and connections between the tool shank and the said locking means for releasing the same.

3. A collapsible tap comprising a hollow body radially slotted at one end, a chaser head mounted to rotate in the slotted end of the body and provided with a spring for turning it to retract the chasers; said head having longitudinally extending curved abutments for backing the inner ends of the chasers, and provided at the base of said abutments with scroll cams, chasers having notched edges engaging said cams and at their inner ends engaging said abutments, means for locking the stem when its spring is under tension, and means for automatically releasing said locking means.

l. A collapsible tap comprising a. hollow body, a chaser operating head and stem mounted to turn in one end of the body to project and retract the chasers, a torsion spring encircling the stem for rotating the chaser head to retract the chasers, means for placing the spring under tension, locking pins for locking the chaser stem when under tension, a tool shank having sliding movement only in the other end of the'body and operatively engaging said locking pins to retract them and release the tension adjusting means. 7

5. A collapsible tap comprising a hollow body provided at one end with radial slots, a chaser head mounted to turn in said slotted end and having integral scroll cams to positively project and retract the chasers, a torsion spring encircling the stem connecting the stem of the chaser head with the body, a collar or locking head fixed to the inner end of said stem and provided with external actuating means for placing the spring under tension, said collar or head having slots or recesses on its lower or rear face, a fixed apertured ring, locking pins extending through the apertures in said ring and engaging said slots or recesses, a sliding tool shank having a head in the opposite end of the hollow body, a spring pressing the head inwardly, and operative connections between the tool shank head and the said locking pins to retract them and release the torsion spring.

6. A collapsible tap comprising a hollow body, a chaser-actuating head mounted to turn in one end of the body and held from longitudinal movement; said head having an operating stem provided with a locking head at its inner end having slots or re cesses, a. handle for said locking head extending outwardly through the body, an apertured adjusting ring next to the slotted or recessed face of said locking head, a tool shank sliding in the opposite end of the body held from rotation therein, and having a recessed head, a spring-pressed ring in said recessed head, an apertured cap plate for the recess, headed locking pins resting on said spring-pressed ring and projecting through the apertures in the cap plate and adjusting ring into the recesses or slots in the locking head of the chaser stem; said adjusting ring having means for setting it from the exterior of the body.

7. In a collapsible tap, the combination with the hollow body, spring-rotated chaser head and stem, a manually rotated head on the stem for rotating it to place the spring under tension; said head having locking slots or recesses in its rear face, an apertured adjusting ring next to said slotted face, means for rotating the ring to change the relation of its apertures to the said locking slots or recesses; the body of the tool having a slot provided with graduations and a part carried by the ring in operative relation to said graduations, a sliding tool shank, and locking pins mounted in the tool shank and passing through the apertures in the adjusting ring into the said locking slots or recesses.

8. A collapsible tap comprising a hollow body, a spring-rotated chaser head in one end of the body and provided with an annular groove, a screw pin projecting through the body into said groove and holding the chaser head against longitudinal movement, a torsion spring encircling the stem of the chaser head for rotating it, chaser-moving scroll cams integral with the rotary head for positively moving the chascrs in and out, means for placing and locking the spring under tension, and a tool shank sliding but not turning in the opposite end of the body and constructed when moved outward in the body to release the locking means and permit the spring to rotate the chaser head and retract the chasers.

9. A collapsible tap comprising a hollow body, a spring rotated chaser head and stem, a manually rotated head to rotate the chaser head and stem against the action of the spring and provided with looking openings or recesses, an apertured adjusting ring ad.- jacent to the rear face of the said head and provided with manually actuated means for rotatively adjusting it, locking pins projecting through the openings in the adjusting ring to engage those in the said head, a tool shank slidingly mounted in the rear end of p the hollow body and operatively connected thereto to rotate it, and connections between the tool shank and the locking pins to withdraw them from the said head.

10. A collapsible tap comprising a hollow body, a spring rotated chaser head and stem, a manually rotated head to rotate the head 1 ioegeos apertures in the said adjusting ring and into the openings in the said head, a tool'shank 1 0 sliding in the rear end of the body and operatively connected thereto to rotate it, and connections between the inner end of the tool shank and the pins to retract them.

In testimony whereof I afiix my si nature. 15

HENRY F. STAHL'BRhDT. 

